1. Technical Field
The subject invention relates to vehicle door latch assemblies having both manual and power door locking features.
2. Description of the Prior Art
Vehicles, such as passenger cars, are commonly equipped with individual door latch assemblies which secure respective passenger and driver side doors to the vehicle. Each door latch assembly is typically provided with manual release mechanisms or lever for unlatching the door latch from the inside and outside of the vehicle, e.g. respective inner and outer door handles. In addition, many vehicles also include an electrically controlled actuator for remotely locking and unlocking the door latches.
As is commonly known, the release mechanisms may be actuated to lock the door latch assembly and prevent release of the outer door handle. However, a thief may break a window of the vehicle and reach inside to manually unlock the latch assembly by actuating the inner door handle. The industry has therefore developed door latch assemblies which have a "double lock" or anti-theft feature which also locks the inner door handle such that neither handle may be actuated to open the door.
The double lock or anti-theft feature is typically accomplished by the electrically controlled actuator and cannot be done manually. This helps ensure that the passengers are outside of the vehicle when the double lock feature is engaged. Examples of prior art door latch assemblies which incorporate a double lock feature are shown in U.S. Pat. Nos. 5,464,260 and 5,474,339. However, the prior art door latch assemblies incorporating the double lock feature have a number of deficiencies.
One primary deficiency relates to the electrical movement of the actuator between an unlocked condition, a locked condition and a double locked condition. A number of elements are actuated within the door latch assembly as the actuator moves between these conditions. The actuator is typically connected to an electric motor which controls the movements. The electric motor must be actuated a predetermined amount in order to move the actuator through the desired conditions. As appreciated, electric motors are susceptible to changes in temperature, moisture, and voltage such that the desired actuation of the electric motor may not be consistently and accurately achieved. Hence, it is desirable to have an electrically controlled actuator which incorporates at least three physical stops to ensure the proper movement of the actuator between the three different conditions.